low-cost porous carbons as electrode materials and technology for purification of these carbons

special technique for electrode/electrolyte preparation together with some peculiarity of SC assembling and pre-starting (aging) procedure

novel methods to significantly reduce ultracap inner resistance

Over the past decade or two ultracapacitors force their way to the market through the strong competition from advanced batteries. Today NiMH and in particular Li-ion batteries demonstrate the power density as high as 0.6-1 kW/kg (though at the expense of lower energy density, shorter cycle life and overheating). Therefore, to become competitive, ultracapacitors must demonstrate the power density much higher than 1 kW/kg providing at the same time the long cycle life. The best of our competitors and ultracapacitor manufacturers demonstrate 1-3 kW/kg at 95% efficiency, while our prototypes demonstrate 5-6 kW/kg.

Fig. 1 Comparison of APC ultracapacitor power and energy density with major competitors:

Fig. 2 Ragone plot based on ITS test results presented at the Advanced Capacitor World Summit, San Diego in July 2008:

Fig. 3 Ragone plot (normalized) based on ITS test results presented at the Advanced Capacitor World Summit, San Diego in July 2008:

Another obstacle for ultracapacitors on the path to the market is cost of carbon. Nanoporous carbon, which is used as electrode material in supercapacitors, is rather expensive, and it typically contributes about 35% to the total cost. APC has utilized carbon, which is 4 times cheaper than that used by its major competitors.

APC middle and large devices can demonstrate the same performance being 2 or 3 times smaller (due to much higher power density), this means that APC uses 2-3 times less material than competitors.